Related papers: Open and Closed-Loop Weight Selection for Pattern …
It has been recently demonstrated that modifying the rim scattering of a paraboloidal reflector antenna through the use of reconfigurable elements along the rim facilitates sidelobe modification including cancelling sidelobes. In this work…
Dynamic modification of the pattern of a reflector antenna system traditionally requires an array of feeds. This paper presents an alternative approach in which the scattering from a fraction of the reflector around the rim is passively…
Radio telescopes are susceptible to interference arriving through its sidelobes. If a reflector antenna could be retrofitted with an adaptive null steering system, it could potentially mitigate this interference. The design of a…
A design methodology for planar loaded antenna arrays is proposed to synthesize a perfect anomalous reflection into an arbitrary direction by optimizing the scattering characteristics of passively loaded array antennas. It is based on…
Reconfigurable Intelligent Surfaces (RIS) have recently gained attention as a means to dynamically shape the wireless propagation environment through programmable reflection control. Among the numerous applications, an important emerging…
Accurate and efficient methods for beam-steering of holographic metamaterial antennas is of critical importance for enabling consumer usage of satellite data capacities. We develop an optimization algorithm capable of performing adaptive,…
We study an inverse scattering problem for a generic hyperbolic system of equations with an unknown coefficient called the reflectivity. The solution of the system models waves (sound, electromagnetic or elastic), and the reflectivity…
Reconfigurable intelligent surfaces (RIS) have recently been proposed as an effective means for spatial interference suppression in large reflector antenna systems. Existing RIS weight optimization algorithms typically rely on accurate…
One of the exciting prospects for large N arrays is the potential for custom beam forming when operating in phased array mode. Pattern nulls may be generated by properly weighting the signals from all antennas with only minor degradation of…
In past work, we described the use of a reconfigurable intelligent surface (RIS) mounted on the rim of an axisymmetric prime focus-fed reflector to create nulls in the close-in sidelobes. In this paper, we show that similar performance is…
Realizing continuous sweeping of perfect anomalous reflection in a wide angular range has become a technical challenge. This challenge cannot be overcome by the conventional aperiodic reflectarrays and periodic metasurfaces or metagratings.…
We propose tunable nonlinear antennas based on an epsilon-near-zero material with a large optical nonlinearity. We show that the absorption and scattering cross sections of the antennas can be controlled dynamically from a nearly…
The ELM method has become widely used for classification and regressions problems as a result of its accuracy, simplicity and ease of use. The solution of the hidden layer weights by means of a matrix pseudoinverse operation is a…
Applying a sparse constraint on the beam pattern has been suggested to suppress the sidelobe level of a minimum variance distortionless response (MVDR) beamformer. In this letter, we introduce a weighted sparse constraint in the beamformer…
We consider a directed variant of the negative-weight percolation model in a two-dimensional, periodic, square lattice. The problem exhibits edge weights which are taken from a distribution that allows for both positive and negative values.…
An electronically reconfigurable dual-band-reflectarray antenna is presented in this paper. The tunable unit cell, a ring loaded square patch with a single varactor diode connected across the gap between the ring and the patch, is modeled…
Applying a sparse constraint on the beam pattern has been suggested to suppress the sidelobe of the minimum variance distortionless response (MVDR) beamformer recently. To further improve the performance, we add a mixed norm constraint on…
Inverse medium scattering problems arise in many applications, but in practice, the measurement data are often restricted to a limited aperture by physical or experimental constraints. Classical sampling methods, such as MUSIC and the…
The design and implementation of low-profile antennas has been analyzed in past decades from different perspectives while the purpose is to have a small size in the device, and an adequate electromagnetic behavior. This work pursues a…
In view of extremely challenging requirements on design and optimization of future mobile communication systems, researchers are considering possibilities of creation intelligent radio environments by using reconfigurable and smart…